Gum inhibitor for hydrocarbon fuels



Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE GUM INHIBITOR FOR HYDROCARBON FUELS No Drawing. Application December 18,

7 Serial No. 415,018

15 Claims.

This invention relates to improvement in means for the protection of liquid hydrocarbon products against discoloration and formation of insoluble and gummy products, and more particularly to improved materials for use with unsaturated liquid hydrocarbons which may be used as fuels.

Liquid hydrocarbons as commercially produced, particularly when prepared by the distillation or cracking of petroleum, possess a tendency to discolor on standing and to form gums and resinous substances. Gasolines produced by the modern cracking processes are extremely complicated mixtures comprising many constituents, the character of these constituents and the relative proportions of different constituents depending upon the source of the crude and the particular cracking process employed. ,Besides the normal and branched chain parafiines, there are often present substantial percentages of aromatic hydrocarbons. The crude cracked gasoline also always contains unsaturated hydrocarbons, such for example as olefines and diolefines. These unsaturated compounds in the presence of air are capable of oxidation to form a series of products, some of which are resinous or gummy. The diolefines, and more unsaturated hydrocarbons, are particularly easily oxidized. Differences in structure other than the degree of unsaturation cause considerable variation in the tendency to oxidize, but in general the ease of oxidation increases with the degree of unsaturation. The more recent pressure methods of vapor phase cracking result in a considerably higher percentage of diolefines than the oldermethods, and it has been stated that these products may run as high as 8 to in unrefined gasoline.

It has been necessary to treat the crude products resulting from the more recent cracking processes in some manner to remove the greater part of these more highly unsaturated products. Among these methods of treatment may be mentioned the sulfuric acid treatment and the 'fullers earth vapor phase treatment. While these methods of purification may remove the greater part of the highly unsaturated compounds, it is found that many brands of gasoline tend to discolor. on storage and to form a certain amount of gum. The gum appears to be a complex mixture of polymerized hydrocarbons, resins, acids, aldehydes. ketones and peroxides. Its formation is distinctly detrimental in all cases. For example. the deposition of gum ingasoline gives 9 sticky substance which deposits upon the walls and bottom of the container, and which may cause serious trouble if formed or deposited in the fuel system of internal combustion engines. The soluble portion of the gum is also objectionable because of 5 the introduction of a non-volatile component into the gasoline.

Our invention has for an object the inhibition of the formation of these insoluble gums and resins, with an attendant improvement in the 1' quality of the gasoline and freedom from the difliculties introduced by the formation of the more or less insoluble and sticky, gummy material, such as irregular gasoline flow in the fuel and lubricating systems of internal combustion 1 engines. A further object is to make it possible to use as an internal combustion fuel, liquid hydrocarbons such as gasoline, that contain larger amounts of highly unsaturated compounds than commercially used at present. A product of this 2 sort can be produced at a lower cost, and possesses in certain cases, improved fuel properties.

We have found that by treating liquid hydrocarbons, such as cracked gasoline or gasoline which has a tendency to form gum, with certain 2 organic compounds, the gum formation can be very appreciably inhibited. More specifically, our invention relates to the use as gum inhibitors of compounds belonging to the class having the general formula (HO):R-NH2, where R rep- 3 resents a polyvalent homocyclic aromatic condensed ring radical which may be unsubstituted or substituted by alkyl, aryl or aralkyl groups, and where :1: represents a whole number which is equal to or greater than 1. By way of illus- 3 trating our invention, the following example is given:

Example-4n this we used the common method of measuring the gum formation in a given hydrocarbon, the method being to evaporate 4 cc. of the hydrocarbon in a copper dish in a steam bath, and to determine the gum residue by the increase in the weight of the dish. When 0.03% 1-amino-2-naphthol was dissolved in freshly distilled cracked gasoline and a 100 cc. 4 portion of the gasoline thus treated was subjected to the copper dish test, the amount of gum formed was 12% of the gum produced from an equal portion of untreated gasoline evaporated in the same way at the same time. The control t sample of gasoline containing no added agent gave 139 mg. gum per 100 cc., whereas the gasoline to which the l-amino-2-naphi7hol had been added formed only 17 mg. gum per 100 cc.

It will be understood that the example outlined I above has been given merely for the purpose of illustrating our invention, and that we do not wish to be limited to the use of the specific inhibitor employed, to the concentration of inhibitor given in the example, nor to any particular type of hydrocarbon fuel. We may use higher or lower concentrations of any members of the class of compounds represented by the general formula and secure a marked decrease in the formation of gum, although the decrease will vary, depending upon-the concentration of inhibitor, the specific inhibitor used, and the nature of the hydrocarbon.

As examples of other compounds falling within the general formula, we may recite the following:

Unsubstituted mouohydric compounds l-amlno-2-naphthol o-en ino-l-naphthoi Substituted monohydric compounds 1:5-dimethyl-3-amino-8-naphthol H OH:

l-phenyl-Z-amlnotnaphthol l-benzyl-t-amino-t -naphthol G aocasee Unsubstituted polyhydric compounds 4-amlno-1: fi-dihydroxy naphthalene H NH:

8-amino-1:4:5-trihydroxy naphthalene N'Hz OH We do not wish to be limited to the compounds recited above as examples of the class falling within the general formula (HO),1--RNH2. may use the isomers or homologues of any of the compounds named above, as well as any compounds which may be described by the general formula.

Since many embodiments of this invention, differing widely in one or more respects, may be made without departing from the spirit of our invention, it is to be understood that we do not limit ourselves to the foregoing examples or description except as indicated in the following claims.

We claim:

1. A cracked gasoline normally tending to deteriorate and form gum upon storage and containing a condensed aromatic ring hydrocarbon substituted by primary amino and hydroxy groups, in quantity suificient to retard such deterioration and gum formation.

2. A cracked gasoline motor fuel normally tending to deteriorate and develop gum on storage and having incorporated therein a compound having the formula HO--R-NH2 wherein R. represents an arylene hydrocarbon radical of the naphthalene series, in quantity suflicient to retard such deterioration and gum formation.

3. A cracked gasoline motor fuel normally tendingto deteriorate and develop gum on storage and having incorporated therein a compound having the formula HO-R-NH2 wherein R represents an arylene hydrocarbon radical containing only threecondensed benzene rings, in quantity sufficient to retard such deterioration and gum formation.

4. A cracked gasoline motor fuel normally tending to deteriorate and develop gum on storage and containing 1-amino-2-naphthol, in quantity sufficient to retard such deterioration and gum formation.

5. A cracked gasoline normally tending to deteriorateand developgum on storage and containing as a gum-inhibitor about 0.03% l-amino- 2-hydroxy-naplithalene.

6. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein a primary amino-hydroxy-carbocyclic condensed ring compound, in quantity sufllcient to retard such deterioration and gum formation.

7. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein a primary amino-hydroxynaphthalene, in quantity suificient to retard such deterioration and gum formation.

aoaacea 8. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein a primary amino-anthranol, in quantity sufficient to retard such deterioration and gum formation.

9. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein l-amino-lO-anthranol, in quantity suflicient to retard such deterioration and gum formation.

10. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein a primary amino-polyhydroxy-naphthalene, in quantity sumcient to retard such deterioration and gum formation.

11. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein a primary mono-aminodihydroxy-naphthalene, in quantity sufficient to retard such deterioration and gum formation.

12. A cracked gasoline normally tending to deteriorate and form gum upon storage and having incorporated therein. 4-amino-l :5-dihydroxynaphthalene, in quantity sufficient to retard such deteriorat on and gum formation.

13. The method of treating a motor fuel comprising cracked gasoline whlch tends to form gum on storage, which comprises adding to said motor fuel a small proportion of a primary amino-hydroxy-carbocyclic condensed ring compound, sufficient to retard gum formation therein.

14. The method of treating a motor fuel comprising cracked gasoline which tends to form gum on storage, which comprises adding to said motor fuel a small proportion of a primary amino-hydroxy-naphthalene, sumcient to retard gum formation therein.

'15. The method of treating a motor fuel comprising cracked gasoline which tends to form gum on storage, which comprises adding to said motor fuel a small proportion of a primary amino-polyhydroxy-naphthalene, suflicient to retard gum formation therein.

HAROLD WALTER ELLEY. HERBERT W. WALKER. 

